The covers of upholstery elements, e.g. the seats of a motor vehicle, are frequently fastened by means of hook-fastener connections which enable simple and rapid fitting as well as removal of the covers for exchange or cleaning purposes. The hook-fastener connection comprises two cooperating strips, of which one is provided with a plurality of hooks, which may be, for example, single hooks, multiple hooks or profile- or mushroom-shaped elements for rear engagement. The hooks engage into mostly loop-like elements of the second strip, which is referred to as the fleece strip. By virtue of a uniform distribution of hooks and the elements cooperating therewith on the strip surfaces, mutual fixing in any desired position relative to one another is possible. Since, as a rule, both the hooks and the loops are made of a flexible material, the connection is releasable by exerting an adequate tensile force, under which hooks and/or elements elastically deform and slide out of one another.
Frequently the strip, which is fastened to the core of the upholstery element and is generally the hook strip, is disposed in a shallow trough. Its projection beyond the surrounding surface of the core is thereby prevented so that a bulging of the cover situated on top and an intrusive raising of the upholstery surface is avoided. The strip fastened to the core is generally provided at the rear with a fibrous web which is incorporated into the foam material of the core.
By virtue of its construction, during a deformation of the hook-fastener connection several hooks as a rule disengage from the loops, with there being, upon termination of the load, mostly a renewed engagement into the same or other loops. If, however, the hook-fastener connection is subjected to a high number of load changes, as is the case particularly when it is fitted on or in the edge region of a seat surface, there is a risk that it will, given time, open independently or that the position of the strips relative to one another will alter. There is moreover in this manner an increased wear of hooks and loops leading to a reduction in the stability under load. Thus, with conventional hook-fastener connections it is impossible to achieve the tear-out resistances which are possible with other methods of fastening the cover, such as a fixing to wire inserts which are incorporated into the foam material of the core. This applies particularly when the fleece strip, as is customary in prior art, is sewn in a U-shape around a seam of the cover so that only a narrow end face of this strip is in contact with the hook strip.